Flooding expected from epic Sierra snowpack

May 2, 2017

The water content of the Sierra snowpack is nearly double the average of long-time measurements. The state's lead water agency conducted the last survey of the wet season Monday. It's now a matter of managing run-off. 

Frank Gehrke with the Department of Water Resources took the year's last snow survey measurement near Lake Tahoe.

Now - for the remainder of the melt season, "there's significant effort looking at how to manage the in-flow to the big reservoirs on the Tuolomne down to the Kings. Because those reservoirs are basically at the maximum they can store for this time of year and yet we have a huge snowpack above that, " Gehrke said.

The airborne snow observatory - a joint project with NASA - will be a key tool in assessing how much water is stored in the snowpack at higher elevations. Gehrke said  it's the most accurate and comprehensive measurement of the Sierra snowpack. And it didn't exist in 2011 - the last time California saw similar conditions. 

Gehrke expects many trails will be snow-covered into late spring. They'll be streams to cross where dry beds were. And in places like Mammoth, on the east side of the Sierra, expect to see bears.

"A big snowpack like this brings the bears down into town - and of course once they get into town they tend not to leave. And you'll see once we get through spring and most of the pack has melted, some of the Sierra wildflowers are going to be pretty spectacular," Gehrke said. 

This week's manual survey showed the water content of the Sierra snowpack at 27.8 inches.